FACT SHEET
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VIBRATION AND STRUCTURAL INTEGRITY
Objective
The Canadian Malartic Mine (CMM) Team wants to harness the creativity of stakeholders to find solutions to eliminate, mitigate or,
if necessary, compensate for vibration-related impacts that its operations may have. We believe that all ideas, from the simplest to
the most complex, deserve to be heard. It is also important to note that solutions put forward during the workshop will be examined
with regard to current and anticipated impacts.
Defining the Problem
› V ibrations that may be caused by mine blasting operations
have an impact on some citizens.
› R esidents living in sectors near the pit report more adverse
vibration-related impacts.
› C itizens
are concerned about the potential impact of
vibrations on the structural integrity of buildings.
› C itizens are concerned about a failure to meet standards
and have asked that CMM systematically disclose its
results.
› T he Monitoring Program put in place for reported damage
to homes does not seem to address the concerns of all
citizens. Some believe that an independent committee of
experts should be established to deal with blasting-related
complaints.
Challenges Faced:
› T he standards that CMM must meet are significant technical
challenges given the mine’s urban location.
› Impacts may be felt across the community because the human
vibration perception threshold is very low, at about 0.5 mm/s.
› E valuating
potential blasting impacts on homes is very
complex. Several buildings in the town are old and some do
not comply with the current building code.
Sources:
› B lasting to extract ore generates vibrations.
› A nearby railroad track and heavy vehicles travelling on road
117 also cause noticeable vibrations in Malartic.
Table: Complaints Received Over the
Past Three Years
Vibration-related Complaints
2012
2013
2014
Number per year
225
155
165
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This fact sheet is a synthesis tool designed to provide food for thought for collaborative workshop participants.
The information it contains has no official value and shall not be construed as CMM undertakings, directions or positions.
BLASTING The
Glossary
breaking of rock by boring in it a hole, which is filled with a blasting charge and
detonated.
BLAST SEQUENCE Successive
detonation of a series of blasting charges, without a time delay between
detonations.
mm/s
Millimetres per second. A
unit of measurement used to measure ground vibration. The
velocity at which the oscillatory movement of the ground moves away from the blasting
point. The greater the speed, the greater the perceived vibration may be. Referred to as
particle speed.
SEISMOGRAPH
Instrument used to measure and record seismic wave data using a ground motion sensor.
FISSUROMETER
Measuring instrument that monitors movements across cracks in a structure.
Influence Factors
last Duration B
Citizens seem more concerned when blasting is of longer duration.
Vibration Velocity The higher the vibration velocity, the greater the likelihood of impact on building structures.
Soil Composition Some types of soil conduct vibrations more efficiently than others.
Precise Location of Work Blasting carried out to the north of the mine site is more likely to be noticed by nearby
residents.
Schedule
lasting is always carried out at the same times – between 11 a.m. and 12 a.m. and between
B
3 p.m. and 4 p.m. – in order to reduce the startle response. Even if citizens are informed of
blasting, some are still startled by the vibrations since blasting can occur at any time during
either timeframe.
Identified Vibration Source
Blasting
› B lasting is carried out at various locations in the pit. The farther the blasting
is to the north, the more it is noticed by citizens.
› B lasting may be carried out no more than twice daily, between 11 a.m. and
12 a.m. and between 3 p.m. and 4 p.m., if the winds are favourable.
› B lasting may include one or several continuous blast sequences, whose total
duration may not exceed 15 seconds. The concept of continuity was imposed
so that there would not be three 5-second blasts with 15-minute intervals
over a period of one hour, which would increase the startle response in
residents. However, blast sequences within a 15-second interval may be
separated by an interval of a few seconds.
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FACT SHEET
1
VIBRATION AND STRUCTURAL
INTEGRITY
Solutions Already Implemented at the
Mine Site
The CMM Team continuously works to improve its practices to reduce the vibration level and mitigate its possible impacts. The
following measures have been taken to date at the CMM site.
Solution #1. Quality Assurance Procedures
Solution #4. Decking
›Q
uality assurance procedures for blasting methods and › D
ecking reduces vibration intensity and the number of blasts
practices have been improved
required
› T he
goal of the clear and precise protocols is to ensure
operational consistency and thus limit the potential for human
error
Solution #5. Call Citizens Before Blasting
› A call program has been implemented to give citizens a twominute warning of blasts
Solution #2. Use of Electronic Detonators
›W
hen a complaint is followed up, the resident concerned is
given
the option of signing up for the call program
› E lectronic detonators allow for better control of blast sequence
synchronization and effectiveness of explosives, while limiting › T
he goal of this approach is to limit the effects of the startle
vibration generation
›O
ne
response
goal is to optimize blasting quality through better
detonation control
Solution #3. Blast Modelling
› I-Blast software enables engineers to anticipate blast results
based on external influence factors, such as the type of rock
and location
Solution #6. Call the Presbytery
› T he Community Relations Team calls the Presbytery
twice a
week to ensure that religious ceremonies are not disrupted by
potential blasting vibration
› C MM
obtains the ceremony schedule and delays planned
blasts when there are church ceremonies
›W
ith modelling, blasting technical parameters can be modified
and blasting can even be delayed if the likelihood that
standards will be exceeded is too great
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1
This fact sheet is a synthesis tool designed to provide food for thought for collaborative workshop participants.
The information it contains has no official value and shall not be construed as CMM undertakings, directions or positions.
Solutions Already Implemented in the Town
of Malartic
The following measures have been taken to date outside the mine site, in the Town of Malartic.
Solution #7. Notice Board Announcing Upcoming Blasts
› T wo notice boards have been installed at either end of the town limits to inform people of the
blasting schedules.
› T he goal is to inform residents and people passing through Malartic of blasts with a view to
reducing the startle response.
Solution #8. Blasting Application Posted on the Mine’s Website
› A blasting application has been posted on CMM’s website in order to keep citizens informed of upcoming blasts, cancellations
and results.
› T he goal is to provide citizens will real-time information.
› T his tool was implemented at the request of citizens
who
wanted to be informed of blast results.
› T his is an additional tool that reduces the impact of the startle
response.
Solution #9. Seismographs
› V ibrations are measured by seven seismographs located throughout the town since 2014.
› T he Ministry selected the locations.
› T he goal is to ensure that standards are
complied with and to validate if improvements
are conclusive.
› T he enhanced program, and data collection and
analysis continue.
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FACT SHEET
1
VIBRATION AND STRUCTURAL
INTEGRITY
Solution #10. Program on Perceived Blasting Effects
› T his program compares residents’ perceptions during blasting with technical data.
› C MM Team members, equipped with portable seismographs, visit residents who are taking part in the program to experience the
blasting with them, in real time.
› A fter the blasting, residents are invited to share their perceived vibration intensity and the effect of the startle response.
› T he evaluations are then compared with the technical data gathered by the seismographs.
› T his program has led to improved practices at the mine. For example, it revealed that blast sequences that start in the north and
end in the south create a stronger startle response in residents. Sequences are now planned to go from south to north.
Solution #11. Control Home Program
› F our homes were fitted with instruments in 2014 to assess the impact of vibrations on structures.
› T he data gathered over the past two years will be compiled so that results can be compared over time and by season.
› T he goal is to acquire the knowledge needed to determine if available studies can be applied to our surroundings.
Solution #12. Fissurometer Monitoring Program
› S eventeen fissurometers were installed on
14 buildings in 2010, before mining began.
› E ight
to nine readings were taken from each
instrument between 2010 and 2014.
›M
onitoring is now done every two weeks to assess
crack growth in the buildings.
› B ased on the data gathered, seasonal temperature
variations seem to have a greater impact on
buildings than building proximity to the mine.
Shifting
Number of
Fissurometers
Percentage per
Movement
0 mm
2
12%
< 1 mm
7
41%
Little movement
< 1.5 mm
5
29%
Slight movement
< 2.5 mm
3
18%
17
100%
Type of Movement
No movement
Very little movement
Total
Solution #13. Building Inspection Program
› A building inspection program, underway since the mining
project was announced and before mining began, targets homes
located within a radius of 150 m from the pit and some control buildings in the town.
› C MM plans to continue these inspections every four or five years.
› T he goal is to monitor the potential impact of operations on buildings.
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This fact sheet is a synthesis tool designed to provide food for thought for collaborative workshop participants.
The information it contains has no official value and shall not be construed as CMM undertakings, directions or positions.
Solution Evaluated and Found to be
Inconclusive
Solution #14. Inspection Mandates – Damage Complaint Follow-up
› A building inspection procedure has been implemented for structural damage complaints.
›D
uring the procedure, an inspection and a report are prepared by an architect or an engineer.
› T he goal is to analyze the cause of the damage.
› B ecause experts determine only the cause of the damage, the procedure fails to address the concerns of citizens who are keen to
know if vibrations caused by mining operations do or do not accelerate the normal deterioration of their home’s structure.
Potential Vibration Sources from the Mine
Extension and Road Deviation Project
The project’s potential vibration impacts are the same as current impacts. Some citizens fear that future blasting carried out in the
Barnat pit will be closer to residential neighbourhoods, but that is not the case. Modelling has shown no increase in impacts on
residents due to vibrations that could be caused by mining operations.
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